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### 33.1 Audio File Utilities

The following functions allow you to read, write and retrieve information about audio files. Various formats are supported including wav, flac and ogg vorbis.

: info = audioinfo (filename) ¶

  Return information about an audio file specified by filename.

  The output info is a structure containing the following fields:

  ‘`Filename`’

    Name of the audio file.

  ‘`CompressionMethod`’

    Audio compression method. Unused, only present for compatibility with MATLAB.

  ‘`NumChannels`’

    Number of audio channels.

  ‘`SampleRate`’

    Sample rate of the audio, in Hertz.

  ‘`TotalSamples`’

    Number of samples in the file.

  ‘`Duration`’

    Duration of the audio, in seconds.

  ‘`BitsPerSample`’

    Number of bits per sample.

  ‘`BitRate`’

    Audio bit rate. Unused, only present for compatibility with MATLAB.

  ‘`Title`’

    `"Title"` audio metadata value as a string, or empty if not present.

  ‘`Artist`’

    `"Artist"` audio metadata value as a string, or empty if not present.

  ‘`Comment`’

    `"Comment"` audio metadata value as a string, or empty if not present.

  See also: audioread, audiowrite.

: [y, fs] = audioread (filename) ¶
: [y, fs] = audioread (filename, samples) ¶
: [y, fs] = audioread (filename, datatype) ¶
: [y, fs] = audioread (filename, samples, datatype) ¶

  Read the audio file filename and return the audio data y and sampling rate fs.

  The audio data is stored as matrix with rows corresponding to audio frames and columns corresponding to channels.

  The optional two-element vector argument samples specifies starting and ending frames.

  The optional argument datatype specifies the datatype to return. If it is `"native"`, then the type of data depends on how the data is stored in the audio file.

  See also: audiowrite, audioformats, audioinfo.

: audiowrite (filename, y, fs) ¶
: audiowrite (filename, y, fs, name, value, …) ¶

  Write audio data from the matrix y to filename at sampling rate fs with the file format determined by the file extension.

  Additional name/value argument pairs may be used to specify the following options:

  ‘`BitsPerSample`’

    Number of bits per sample. Valid values are 8, 16, 24, and 32. Default is 16.

  ‘`BitRate`’

    Valid argument name, but ignored. Left for compatibility with MATLAB.

  ‘`Quality`’

    Quality setting for the Ogg Vorbis compressor. Values can range between 0 and 100 with 100 being the highest quality setting. Default is 75.

  ‘`Title`’

    Title for the audio file.

  ‘`Artist`’

    Artist name.

  ‘`Comment`’

    Comment.

  See also: audioread, audioformats, audioinfo.

: audioformats () ¶
: audioformats (format) ¶

  Display information about all supported audio formats.

  If the optional argument format is given, then display only formats with names that start with format.

  See also: audioread, audiowrite.

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